Sow seed indoors under lights or in a greenhouse and use bottom heat to promote uniform emergence. Select a well-drained media and target a temperature of 75°F/24°C. Moisten the media prior to sowing and then sow the seed. Afterwards, apply a light cover of medium-sized vermiculite. Do not water in the seedlings following sowing or the day after sowing (keep the vermiculite dry). Then, water as needed to maintain uniform moisture. Seeds germinate in about one week. Seedlings may be transplanted into 4-inch/10 cm. pots or cell packs about 3 weeks after sowing or when roots fill the starter cell. Transplant outdoors after all danger of frost is past and the weather is warm and settled. Zinnia Profusion will ultimately grow up to 14 inches/35 cm. tall and 24 inches/60 cm. wide. However, in cooler northern climates, with a shorter growing season, the plants often are smaller. The Profusion Double series is highly disease tolerant, but cool temperatures (below 60°F/15°C) induces disease problems; especially under wet and rainy conditions. Poorly drained soil or overwatering induces root disease. You can enjoy pretty flowers from summer to autumn.